Long-term outcomes of isolated superficial vein thrombosis in patients with active cancer

Background: Cancer patients who develop a deep-vein thrombosis (DVT) or a pulmonary embolism (PE) are at higher risk of death than similar cancer patients who do not develop DVT or PE. The impact of isolated superficial venous thrombosis (SVT) (i.e. without DVT or PE) on the prognosis of cancer patients is unknown. Methods: Data from the OPTIMEV, multicentre, observational study, to compare at 3 years the incidences of death, DVT-PE recurrence and bleeding of cancer patients with objectively confirmed SVT vs. cancer patients with DVT (matched 1:2 on age, sex, cancer stage) and vs. patients with SVT without cancer (matched 1:3 on age and sex). Results: Cancer patients with SVT (n = 34) had a high risk of death (23.2% patient-year(PY)), that was similar to that of cancer patients with DVT (aHR = 1.0[0.6-1.9]) and higher to that of SVT patients without cancer (aHR = 9.0[3.5-23.1]). Cancer patients with SVT received anticoagulants for a median duration of 45 days and had a high risk of DVT-PE recurrence (6.0%PY), similar to that of cancer patients with DVT (adjusted cause-specific HR (aCHR) = 1.5[0.4-5.8]) and higher to that of SVT patients without cancer (aCHR = 2.9[0.7-11.9]). In our population, venous thrombosis on varicose veins was associated with a lower risk of death (aHR = 0.6[0.3-1.0]) and DVT-PE recurrence (aCHR = 0.6[0.2-1.7]). Conclusion: Our results suggest that cancer patients with SVT have a poor prognosis, similar to that of patients with cancer-related DVT. The high rate of DVT-PE recurrence suggests that such patients may need longer duration of anticoagulant treatment.